Tuesday, December 2, 2008

TANCET Math prep question - Linear Equations

Linear Equations is one of the fundamental topics from which you could expect one or two questions in the TANCET test.

A Linear Equation is one in which the power or the exponent of the variable is 1. An equation of the form 3x + 2y = 17 is a linear equation.

A linear equation in two variables x and y represents a straight line when plotted on a x - y plane. The equation of the x-axis is y = 0 and that of the y-axis is x = 0.

The following question is a word problem in linear equation. You will be presented some information as a statement and you will be expected to fram linear equation based on the information provided there and solve the linear equation to get the answer.

QuestionRam's father is thrice as old as Ram. 6 years hence, his father will be 24 years older than Ram. How old is Ram?
1. 24 years
2. 18 years
3. 12 years
4. 36 years
5. 42 years

Correct Answer and Explanation
Let Ram's present age be R.
So, his father's present age is 3R.

6 years hence, Ram will be (R + 6) years old
6 years hence, Ram's father will be 3R + 6 years old.
The question states that 6 years hence, Ram's father is 24 years older than Ram.
i.e., 3R + 6 = (R + 6) + 24

Or 3R + 6 = R + 30
or 2R = 24 or R = 12.
Ram's present age is therefore 12 years.

Shortcut Approach
You should actually solve this question by going back from the answer choices. That way, you will save a lot of time. Anyone who is serious about cracking the TANCET should commence your preparation for the TANCET exam not later than the day your fifth semester exams are over if you are in a 3-year degree program or after your seventh semester exam gets over if you are in a 4-year degree program.